Diffuser



Nov. 23, 1937. A, MA K 2,099,761

DIFFUSER Filed Dec. 14, 1936 Patented Nov. 23, 1937 UNITED STATES PATENT OFFICE 3 Claims.

This invention relates to lighting devices and more particularly to lighting devices for use in connection with desk lamps and the like and in which the socket is preferably mounted on a short flexible standard whereby the light may be directed as desired by flexing the standard.

It is an object of the present invention to provide a lighting device and particularly an attachment for standard desk lights whereby the light rays may be diffused over a predetermined area in a manner to provide a soft, pleasant light which is not injurious to the eyes of the user, and whereby artificial light from the usual desk lamp may be transformed into illumination closely approximating daylight.

A further object is to provide a lighting device which will increase the utility of the ordinary study lamp and provide efficient lighting at a low cost and in which injurious light rays will be filtered and other rays diffused.

A further object is the provision of an attachment for the usual desk or study light which will provide the above-noted desirable diffused filtered light over a predetermined area and which will also provide a certain proportion of unfiltered illumination, particularly at the outer edges of the diffused area where the diffused light is not required.

It is also an object to provide a device of the character described which will be easily attached to the ordinary study lamp and which will provide efficient air circulation throughout the reflector, and also one which may be cheaply and easily manufactured and assembled and will not easily get out of order.

A further object is to provide a daylight attachment of the character described which is of few parts, easily assembled, cheap to manufacture, and which may easily be attached to the usual desk light and conveniently adjusted to meet the requirements of the user.

Further objects will be apparent from the specification and the appended claims.

In the drawing,

Figure 1 is a side elevation of the upper part of an ordinary study lamp with the reflector and diffusing lens illustrated in axial section.

Fig. 2 is a bottom view of the embodiment illustrated in Fig. 1.

Fig. 3 is a perspective view of the assembled lens-supporting bracket.

Fig. 4 is a diagrammatic view illustrating the relative position of the lens to provide air circulation in the reflector and also undiffused illumination around the diffused light area.

Referring to the drawing in detail, the embodiment illustrated comprises the usual stand lamp having a flexible socket support I for the passage of conductors therethrough and a socket 2 secured to the support and arranged to receive the usual 5 electric bulb 3. A shade or reflector 4 is provided with a threaded tubular portion 5 which is arranged to be screwed onto the'usual threads 6 of the socket and to be supported thereby. The reflector 4 may be any of the usual types, but is 10 preferably a parabolic half shade as illustrated, the opening of which is circular in form and the rim is positioned horizontally with the lamp and somewhat below the light source, as shown.

A convex lens fl is mounted below the globe 3 15 and preferably concentric with the shade 4, and with its upper edge substantially parallel with or slightly below the rim of the reflector. The lens 1 is preferably slightly smaller in diameter than the opening in the reflector to permit undiffused and 20 unfiltered light rays to pass through the space 8 between the diffuser and the reflector whereby an area surrounding the predetermined diffused area may be illuminated by undiffused and unfiltered light. 25 The lens 1 is supported on the socket by means of a suitable bracket, indicated generally by the reference character 9. This bracket comprises a lens-engaging member I 0 arranged to engage the lower curved surface of the lens and having a 30 clamping member ll formed at l2 to extend over the rim of the lens without contacting therewith, whereby the forward down-turned end or lip l3 may clamp the lens securely in position against the member I0. 35

A resilient pad I 4 is inserted between the clamping portion or lip 13 and the lens 1 to prevent accidental breakage of the lens. The opposite end of the supporting member I0 is pivoted at I5 to a pair of interchangeable socket-clamping members it which are formed to engage the socket immediately back of the threaded portion 6. The pivot l5 preferably comprises a screw having a suitable thumb nut ll thereon for clamping the lens in any desired adjusted position. 45

A resilient split washer I8 may be inserted between the thumb nut and the adjacent clamping member whereby the lens may be clamped in any desired position and then may be moved, as shown by dotted lines in Fig. 1, without disturbing the 50 clamping relationship. While the lens is not in use, it may be moved rearwardly and completely out of the path of the light rays, or it may be adjusted in any desired position relative to the light source.

The lens 1 is preferably of the so-called daylight type and may be provided with a so-called ground glass inner surface, which surface may be produced by sand blasting or any suitable method.

It will be apparent that the invention provides a cheap and eflicient lighting device which may be easily adjusted to meet all ordinary requirements, which will provide adequate ventilation and which provides approximately uniform illumination over -a wide field.

Further modifications will be apparent to those skilled ml the art, and it is desired, therefore, that the invention be limited only by the prior art and the scope of the appended claims.

Having thus vdescribedmy invention, claim and desire to secure by Letters Patent is;

1. An attachment for half shade desk lights comprising a concavo-convex diffuser having a peripheral rib on the concave side, a support comprising a clamp portion substantially conforming to the convex side adjacent the periphcry of said'difiuser, a complemental clamping memberv arranged to clamp said diffuser inside said rib, means outside the periphery of said diffuser for securing said clamping member to said clamp portion, said clamping member having a groove providing clearance for said rib to enable clamping of said diffuser inside said rib, said clamp portion having an arm extending outwardly beyond said clamping member, interchangeable socket clamping members pivotally mounted on said arm to provide a hinge, and means for adjustably securing said hinge to permit relative frictional adjustment of said diffuser.

what I members pivotally mounted one on each 2. An attachment for a half shade desk light, having an electric light socket, comprising a concavo-convex diffuser having a peripheral rib on the concave side, a support comprising a clamp portion substantially conforming to'the convex side adjacent said rib, a complemental clamping member arranged to clamp said difiuser inside said rib and having a groove to provide clearance for said rib, a resilient pad between said clamping member and said difluserymeans outside the periphery of said difiuser, and closely adjacent said rib for securing said clamping member to said clamp portion, said clamp portion having an arm extending outwardly beyond said clamping member, interchangeable socket clamping side of the outer end of said arm to provide al hinge therebetween, and means for adjustably securing said hingetogether to clamp said attachment to said socket and to simultaneously secure said hinge to permit frictional adjustment of said diffuser.

3. An attachment for a desk light comprising a diffuser, clamping members for clamping the edge of said diffuser therebetween, means closely adjacent the edge of said difiuser for securing said members together in clamping relation, a rearwardly extending arm on one of said members, a pair of interchangeable straps pivotally mounted on said arm and substantially conformcontour of a socket, and means for ing to the clamping said arm and said straps together to form a frictional hinge therebetween and simul- I taneously clamping said straps on a socket.

. GEORGE A. MARKS. 

